Lord Of The Rings: oh to play it again one day...

My LOTR's DMD was crisp and clear, no lines missing. One day when playing, the DMD just went blank. No glow, no lines, no single pixels.
I turned the game off. Next day, it played fine and bright and clear.
Happened again a week later (I was playing sparingly,) was displaying fine, then the DMD turned off mid-game. Turned the game off, then tested it the next day, and the DMD turns on fine.
Then it happened a third time, and now the DMD won't come back on at all.
Does this sound familiar to anyone? Seems like odd behaviour.
5V LED light on the DMD back is on.
I tried reseating all of the cables, then tried jostling them a bit, didn't help.
I unplugged the cable from the power and tested the power supply outputs. Got all good readings, except the 12V was reading as 0, but I don't didn't see that the 12V did anything in the schematics. Then found an old RGP post saying that 12V wasn't used, so not that?

soooo that 12V goes nowhere?

Also there have been a few other stuck ball issues, like the ball getting stuck at the bottom of the Legolas ramp, or in the Gimli VUK, wedged between the post and the wire ramp, sometimes with the help of the Balrog toy.

These issues are addressed in this post, and I will look to follow their fixes.

I really wish I could be playing this classic game!  It's spent far too long out for service, considering how long I had to wait for that darn switch switch to arrive.

I guess I could play it without the DMD?  But mehhhhh